The former star claims she went under the knife to remove 'webbed' skin that was growing between her nose and her eyes.
The 27-year-old star wrote: 'I had a nose job to remove skin that was like a webbing in between my eyes. Having surgery was the most amazing thing for my confidence!'
She wrote: I wasn't going to tell anyone, but I look so much prettier in my new photos that I don't want old photos used anymore!
'I'm so sick of magazines and blogs using old photos! When will they stop? I will never look like that again!'
Amanda has recently sparked concern for her welfare after displaying erratic behaviour, including tweetoing near-naked photos of herself and shaving half her head.
But she reached out to her worried parents, Lynne and Rick, this week, months after cutting off all contact with them.
A source previously said: 'Amanda reconnected with her parents this week and it was a really positive talk on both ends.
'Her parents are good people who are genuinely concerned for her. And Amanda misses them, so she finally called them up.'
The actress, who admitted she is suffering from an eating disorder and wants to weigh 100 pounds, recently started posting raunchy tweets and topless photographs of herself online.
She settled two hit-and-run cases after reaching a civil compromise with her victims, saving herself from a potential 12 months in jail in December.